Place the beef stew meat, potatoes, carrots, onion, and garlic into the slow cooker.
In a small bowl, whisk the flour with 1/4 cup of the apple cider until smooth, then pour this mixture into the slow cooker.
Add the remaining apple cider, beef broth, thyme, bay leaves, salt, and black pepper. Stir gently to combine everything.
Cover and cook on low for 8 hours, until the beef is fork-tender and the gravy has thickened.
Remove the bay leaves before serving.